Enhanced apoptosis of ABT-737 combined to a proteasome inhibitor in DLBCL (RL) and MCL (HBL-2). (A) Treatment of RL cells with ABT-737 at 100 nM and bortezomib (B) at 10 nM induces apoptosis in more than 50% of cells (P < .001). (B) Treatment of HBL-2 cells with ABT-737 at 10 nM and bortezomib (B) at 6 nM or carfilzomib (C) at 10 nM induces apoptosis in more than 80% of cells (P < .001). Apoptosis. was evaluated by cytofluorimetric analysis of yo-pro-1 and propidium iodide. Results represent the average plus or minus SD. * Early apoptotic: yo-pro-1–positive and PI–negative; ** late apoptotic: yo-pro-1–positive and PI–positive.